Controlling quality is an important part of any production process. In semiconductor production, it is important to reduce and control defects on semiconductor components. Conventionally, semiconductor manufacturing facilities employ a particle-per-wafer pass (PWP) defect control to measure defects on monitor wafers at various points along a production line. PWP defect control utilizes various monitors to automatically count defects on the monitor wafers. The monitors provide quantitative and qualitative information about any defects detected on the monitor wafers.
The PWP defect control is a statistical process control (SPC) that detects and monitors defect trends and triggers alarms when defect limits exceed statistically determined SPC limits. Conventional monitoring systems monitor a single process in an overall production system and provide feedback to a user or process engineer regarding the process monitored. The user or process engineer reviews the feedback to determine what corrective action, if any, is required for the monitored process.